OBJECTIVES: Characterization of natural cytotoxicity and natural killer cells. Comparison with lymphocytes that mediate antibody-dependent cell-mediated cytotoxicity (ADCC) against Chang liver cells. Study of the generation of natural cytotoxicity and ADCC in 5-7 day cultures. Enhancement of these activities by co-cultures with various antigens, mitogens and with tumor cells, immunoadjuvants and interferon. Comparison of these activities with the generation of specific immune T lymphocytes in mixed lymphocyte cultures. Use of continued cultures of pure T lymphocytes from any given individual and characterization of their functional activities. Immunological monitoring of patients with lung and breast cancer, Ewing's sarcoma, and melanoma. Adjuvant chemotherapy and immunotherapy with BCG, C. parvum, and poly I:C. Skin tests with purified, soluble extracts of tumor cells. In vitro assessment of immunocompetence, natural cytotoxicity, and tumor immune reactivity, by short-term cytotoxicity assays, mixed lymphocyte tumor cell culture, and leukocyte migration inhibition. Reactivity of subpopulation of lymphocytes. Examination of cells from various lymphoid organs and from the tumor.